[USRP-users] Phase coherence problems using TVRX2
john.malsbury at ettus.com
Thu Jun 14 12:29:02 EDT 2012
I forgot to mention that we do have a new knowledge base up. There is a
document you'll find there that explains the requirements for a MIMO
system that can be used for direction of arrival measurements.
I recommend taking a look: www.ettus.com/kb
Search "MIMO" if you can't find the document in the menus.
On 06/13/2012 11:06 AM, Lucas Caldeira de Oliveira wrote:
> I'm working on a project that uses a linear array with four antennas
> for direction of arrival measurement. In this scenario,
> phase-coherency between each antenna is necessary.
> I'm using one USRP rev4.5 with two TVRX2 rev1.1. I found that a random
> phase offset is occuring every time i execute the program. After LO
> lock, the phase offset remains constant.
> Inside FPGA, the phase accumulator is the same for four DDCs. These
> signals between the input of ADC and inside GNURadio are phase
> coherent. This random phase offset is occuring inside TVRX2.
> I'm using the last version of UHD and GNURadio.
> Could you give us information about this problem? Is it possible to
> achieve phase coherency between these signals? Is there any limitation
> in TVRX2 about this?
> USRP-users mailing list
> USRP-users at lists.ettus.com
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